Heating oils



' made .to users.

Patented July 28, 1942 HEATING OILS William J. Backofl and Norman D. Williams, Chicago, John F. OLoughlin, Winnetka, Harry L. Moir, Niles Center, and John S. Yule, Chicago, Ill., assignors to The Pure Oil Company, Chicago, 111., a corporation of Ohio No Drawing.

Application July 29, 1940,

Serial No. 348,284

15 Claims.

This invention relates to new and useful fuel oils useful for heating purposes by being burned in domestic and commercial oil burner installations and is particularly concerned with a method of preventing clogging and fouling of fuel oil burners.

In the operation of oil burning equipment for -cosity from 50 to 100 seconds Saybolt Furol at 122 F., or even higher. The distillate grades of fuel oil are generally used in domestic heating installations while the heavier residual fuel oils are confined largely to commercial and industrial applications. The proper grade of fuel oil for a given oil burning system is ordinarily determined by the manufacturer of the oil burning equipment and appropriate recommendations As long as the manufacturer's recommendations are followed as to the grade of fuel oil used, reasonably satisfactory operation is generally attained. However, it is generally recognized that even though the recommended grade of fuel oil is used, periodic removal of gummy and carbonaceous deposits from the strainers, nozzles and needle valves of oil burning equipment must be resorted to in order to,

maintain the equipment in proper operating condition. It is highly desirable that the periods between cleaning of the equipment be as long as possible in order that maintenance expenses may be kept at a minimum and a minimum of interruption in operations obtained.

The rapidity with which oil burning systems become fouled with such deposits is greatly increased when a heavier grade of heating oil is used than that for which the equipment is designed. The tendency to use fuel oil heavier than that for which the burning equipment is designed is readily apparent when it is understood that the heavier grades of fuel oil are appreciably cheaper than the lighter grades of fuel oil. Further, the heavier grades offuel oil possess a greater B. t. u. content, and hence are more economical in use. ential prevailing, there is a definite tendency on With such economical differ-I the part of heating oil users to endeavor to burn oil of a heavier grade than that for which the oil, burning equipment is designed, even though the maintenance cost and interruptions in operations may at times more than offset the savings in price effected through purchase of the heavier grade of fuel oil.

It is an object of this invention to provide heating oil compositions having a reduced tendency to deposit gummy carbonaceous material in oil burning equipment.

It is another object of this invention to provide compositions of residual heating oils which have a greatly reduced tendency to foul the oil burning equipment in which they are used.

A further object of this invention is to provide a method of preventing the fouling of oil burning equipment. I

A still further object of this invention is to provide a method of cleaning nozzles and screens and other working parts of oil burning equipment which tends to become fouled by the heating oil used therein.

Further objects of the invention will appear from the following detailed description.

It has been discovered that by incorporating a suitable anti-fouling agent or solvent in heating oil the tendency of the oil to foul the oil burning equipment by depositing gummy carbonaceous residue in screens, nozzles, and needle valves and other working parts of the oil burning equipment is greatly reduced and in thosev cases where the oil burning equipment has already been fouled by the deposition of such material, the deposits may be substantially removed with consequent improvement in the efficiency of the operation, all of this being accomplished without disassembling the equipment or interrupting the operation of the burner. The materials used in preparing the solvent in accordance with this invention are: (1) compound or a mixture of compounds boiling over 350 F. having excellent gum solvent properties at elevated temperatures and which may or may not have good gum solvent properties at ordinary temperatues and which are seselected from the group consisting of esters of aliphatic dicarboxylic acid, esters of aromatic acids, cyclic ketones (including aromatic ketones), and aliphatic alcohols; and (2) a compound or a mixture of compounds boiling below 350 F. having good gum solvent properties at ordinary temperatures and which are selected.

from the group consisting of esters of aliphatic acids, aliphatic alcohols and aliphatic ketones. As examples of group (1) may be mentioned amyl phthalate, benzyl benzoate, ethyl benzoate, dibutyl phthalate, dibutyl tartrate, butyl benzoate, acetophenone, furfuralacetone and octyl alco- 1101. Examples of group (2) are: ethyl butyl various compounds indicated which may be used in such combinations of solvent materials must for satisfactory results be maintained within certain definite ratios but may be varied within the limit of 25% to 90% by volume of one or more materials selected from group (1) and 75% to 10% by volume of one or more materials selected from group (2). It is only by maintaining the compositions between these limits that effective prevention of fouling of oil burning equip ment may be effected.

The composition is preferably used in admix ture with heating oil, although it may be injected directly into the oil burning equipment, for example, into the fuel oil feed line. It has been found to be advantageous in those systems where there is a definite tendency for the operation to become impaired through deposition of gummy material, to periodically, for example, everv month, or every three months, add about eight to sixteen ounces of the solvent mixture through the fuel oil feed line. This amount, however, may be subject to considerable variation, depending upon the size of the fuel oil burning system, and the amount of deposit generally encountered therein.

The quantity of such solvent mixture which when added to heating oil, effectively removes and/or minimizes the tendency to deposit gummy carbonaceous material in oil burning systems, may vary considerably depending upon the type of burner, condition of the oil. burning system, the particular fuel employed,and the operating conditions encountered. A maximum of 5% and usually not over 1% of solvent, based onthe volume of heating oil, is preferred. In general, it has been found that from 0.1% to 1% of solvent gives very satisfactory results. In any event it isnecessary to avoid using sufllcient solvent to reduce the flash point of the fuel oil below that required of the particular fuel. In some cases, particularly when the solvent is injected directly into the burner system, it has been found advantageous to disperse or dissolve the solvent in a suitable carrier liquid or vehicle prior to introduction of the solvent mixture into the oil buming system. The carrier liquid may suitably consist of to 50% by volume of the total mixture. A suitable carrier liquid for this purpose is a mineral oil of low viscosity or fuel oil, particularly distillate type fuel oil. Carrier liquids that are preferred are non-lubricating petroleum oils of fuel oil boiling range. By nonlubricating oils it is intended to'include only those oils that are generally considered to be unsuitable for lubricating purposes, for example, kerosene, gas oil and residual black oils of high asphaltic content.

As a specific example of a highly useful solvent, parts by volume of mineral oil having the following characteristics:

so Viscosity at'-100 70-75 Color, Saybolt Flash C. O. C F 350-360 Fire, F 400-420 tate. This mixture may, for example, be added to heating oil in the proportion of 99.75% heating oil and 0.25% solvent mixture. When this heating oil-solvent mixture is used in oil burning systems, it effectively minimizes the tendency toward formation of gummy carbonaceous deposits and in those systems where deposits are already present and interfering with efficient operation, the deposits are substantially decreased, and/or removed, restoring the burning system to higher operating efficiency. The mineral oil-solvent mixture may be directly injected into the oil burning structure to expedite the cleaning thereof.

In a specific application the aforesaid solvent mixture was added to number 3 heating oil in the proportion of 0.25% by volume. The number 3 fuel oil had approximately the followingcharacteristics:

End point F 630 Carbon residue "percent" 0.03 Pensky-Marten flash.- F 140 Saybolt viscosity at 100 F seconds 35 B. t. u. gal L 142,000

experienced with the clogging of screens and" nozzles. The number 1 fuel oil had approximately the following characteristics:

' End point F 560 Pensky-Marten flash F 130 Pour point "F Less than 0 B. t. u. gal 137,000

is blended with 40 parts by volume of dibutyl When the aforementioned blend of the same number 3 fuel oil which had formerly been used, but which contained 0.25% of solvent mixture, was used, it was possible to operate the burner for a period of over two months without any service requirements. -An inspection at the end of that period of operation showed that the clean as when the burner ing the periods of trouble-free operation.

Although the use of novel anti-fouling solvent in accordance with this invention has been more particularly described in connection with distillate fuel oils, it is to be understood that the solvents are equally or even more effective when incorporated in residual type fuel oils, thus permitting the use of residual fuel oils in applications where such oils would normally not be usable due to their fouling tendencies. The invention is not limited to the specific examples described or to any particular theory or mechanism of the action of the solvent additive but is to be interpreted as broadly as the prior art permits in view of the following claims.

We claim:

1. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boiling range of gasoline containing from 0.1% to of a mixture containing 25% to 90% of oxygen-containing material boiling above 350 F. having gum solvent properties at elevated temperatures and selected from the group consisting of esters of aliphatic dicarboxylic acids, esters of aromatic acids, cyclic ketones and aliphatic alcohols, and 75% to of oxygen-containing material boiling below 350 F. having gum solvent properties at normal temperatures and selected from the group consisting of aliphatic esters, aliphatic ketones and aliphatic alcohols.

2. An anti-fouling heating oil comprising n'onlubricating petroleum oil boiling above the boiling range of gasoline containing from 0.1% to 5% of a mixture containing 25% to 90% of ester of aromatic acid boiling above 350 F. having gum solvent properties at elevated temperatures, and 75% to 10% of ester of aliphatic acid boiling below 350 F. having gum solvent properties at normal temperatures.

3. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boiling range of gasoline containing from 0.1% to 5% of a mixture containing 25% to 90% of ester of aromatic acid boiling above 350 F. having gum solvent properties at elevated temperatures, and 75% to 10% of aliphatic ketones boiling below 350 F. having gum solvent properties at normal temperatures.

4. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boiling range of gasoline containing from.0.1% to 5% of a mixture containing 25% to 90% of ester of aromatic acid boiling above 350 F. having gum solvent properties at elevated temperatures, and 75% to 10% of aliphatic alcohol boiling below 350 F. having gum solvent properties at normal temperatures.

5. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boiling range of gasoline containing from 0.1% to 5% of a mixture containing 25% to 90% of ester of phthalic acid boiling above 350 F. having gum solvent properties at elevated temperatures, and 75% to 10% of ester of aliphatic acid boiling below 350 F. having gum solvent properties at normal temperatures.

6. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boiling range of gasoline containing from 0.1% to 5% of a mixture containing 25% to 90% of ester of phthalic acid boiling above 350 F. having gum solvent properties at elevated temperatures and r 75% to 10% of ester of acetic acid boiling below 350 F. having gum solvent properties at normal temperatures.

7. An anti-fouling heating oil comprising nonlubricating petroleum oil boiling above the boil.- ing range of gasoline containing from 0.1% to 5% of a mixture containing 25% to 90% dibutyl phthalate and 75% to 10% ethyl acetate.

8. Method of removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises flowing through said nozzles a. mixture comprising a major portion of the following materials in the following proportions: (1) oxygen-containing material boiling above 350 F. having gum solvent properties at elevated temperatures and selected from the group consisting of esters of aliphatic dicarboxylic acids, esters of aromatic acids, cyclic ketones and aliphatic alcohols-25% to 90%; (2) oxygen-containing material boiling below 350 F. having gum solvent properties at normal temperatures and selected from th group consisting of aliphatic esters, aliphatic ketones and aliphatic alcoholsto 10 9. Method of removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises flowing through said nozzles a mixture comprising a major portion of the following materials in the following proportions: (1) ester of aromatic acid boiling above 350 F. having gum solvent properties at elevated temperatures25% to (2) ester of aliphatic acid boiling below 350 F. having gum solvent properties at normal temperatures-75% to 10%.

. 10. Method of removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises flowing through said nozzles a mixture comprising a major portion of the following materials in the following proportions: (1) ester of phthalic acid boiling above 350 F. having gum solvent properties at elevated temperatures-25% to 90%; (2) ester of acetic acid boiling below 350' F. having gum solvent properties at normal temperatures75% to 10%.

11. Method of removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises flowing through said nozzles a mixture comprising a major portion of the following materials in the following proportions: (2) dibutyl phthalate2 5% to 90%; (2)

ethyl acetate'75% to 10%.

12. Method of preventing gum deposits in and removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises injecting into the nozzle together with the fuel oil to be bumed therein a total of 0.1% to 5% by volume based on the fuel oil, of the following materials in the following proportions: (1) oxygen-containing material boiling above 350 F. having gum solvent properties at elevated temperatures and selected from the group consisting of esters of aliphatic dicarboxylic acids, esters of aromatic acids, cyclic ketones and aliphatic alcohols-25% to 90%; (2) oxygen-containing material boiling below 350 F.

having gum solvent properties at normal temperhaving gum solvent properties at elevated temperatures-25% to 90%; (2) ester of aliphatic acid boiling below 350 F. having gum solvent properties at normal temperatures-75% to 10%.

14. Method of preventing gum formation in and removing gum deposits from oil burning nozzles used in conjunction with heating systems which comprises injecting into the nozzle together with the oil to be burned therein a total of 0.1% to 5% by volume, based on the fuel oil, of the following materials in the following proportions: (1) ester of phthalic acid boiling above 350 F. having gum solvent properties at elevated temperatures-25% to 90%; (2) ester of acetic acid boiling below 350 F. having gum solvent properties at normal temperatures-75% to 10%.

15. Method of preventing gum deposits in and proportions: 1) dibutyl phthalate 25% to removing gum deposits from oil burning nozzles 90%; (2) ethyl acetate-75% to 10%.

used in conjunction with heating systems which WILLIAM- J. BACKOFF. comprises injecting into the nozzle together with NORMAN D. WILLIAMS. the oil to be burned therein a total of 0.1% to 5 JOHN F. OLOUGHIJN. 5% by volume, based on the fuel oil, of a mix- HARRY L. MOIR.

ture of the following materials in the following JOHN S. YULE. 

